For the purpose of electrically connecting test contacts on the grid of a printed circuit board testing device with test points of a test piece that are on and/or off the grid, an adapter is fitted with test pins corresponding in number to the number of test contacts or test points, the test pins being inserted in the adapter at various inclinations so that they connect the test contacts and test points and their ends form contact points for the test contacts or test points as the case may be. Fitting the adapter with the test pins can be done either manually or mechanically, and either semi-automatically or fully automatically.
A test pin of the kind described above is the subject of an earlier proposal by the applicant. In this arrangement the test pin has a cylindrical shaft as a guidance section that is tapered conically to a point at the end, the angle of the point being about 90.degree.. The pointed end forms the contact section of the test pin.
Forming such a relatively blunt tip on the test pin has the following purpose. In the arrangement described above the test pin can be pushed into guide hole sections that extend through superimposed guide plates of the adapter. To ensure that the tip of the test pin is introduced into each successive guide hole in the guide plates the guide holes are displaced relatively to each other so that the tip of the test pin lands inside the rim of each successive guide hole. Thus on each encounter the test pin is guided on the rim of a hole and into that hole and thus into the correct position.
This known arrangement has proven to be very advantageous, but it still needs to be improved, for the following reasons. Because of the predetermined thickness of the test pin it is only possible to test test-pieces whose test points are relatively far apart. This limits the field of use of this adapter, particularly for so-called SMD test pieces.